* {
    margin: 0;
    padding: 0;
}

#screen {
    position: fixed;
    width: 100%;
    height: 100%;
}

#form{
    position: absolute;
    width: 100%;
    height: 5%;
    min-height: 30px;
    border: 1px solid;
}

.btnPlay{
    margin: 10px;
    position: relative;
    width: 30px;
    height: 30px;
    border: 5px solid blue;
}